Abstract
Two-dimensional hydraulic modeling is fundamental to simulate flood events in urban area. Key factors to reach optimal results are detailed information about domain geometry and utility of hydrodynamic models to integrate the full or simplified Saint Venant equations in complex geometry. However, in some cases, detailed topographic datasets that represent the domain geometry are not available, so approximations—such as diffusive wave equation—is introduced whilst representing urban area with an adjusted roughness coefficient. In the present paper, different methods to represent buildings and approximation of the Saint Venant equations are tested by performing experiments on a scale physical model of urban district in laboratory. Simplified methods are tested for simulation of a real flood event which occurred in 2013 in the city of Olbia, Italy. Results show that accuracy of simulating flow depth with a detailed geometry is comparable to the one achieved with an adjusted roughness coefficient.
Highlights
Flood events are one of the most dangerous natural phenomena connected to human activities, with possible consequences on people’s safety and economic losses [1].The flood hazard affecting densely populated areas is increasing in recent times, due to the intensification of extreme meteorological events and poorly managed urban development [2].Two-dimensional flood inundation modeling is a pivotal component of flood risk assessment and management
This is relevant when one flood event has to be simulated in an urban area for which detailed buildings geometry is not available
InInthis three different methods toto simulate the influence ofof buildings ononflood thispaper, paper, three different methods simulate the influence buildings floodinundation inundation have been tested against measurement undertaken on a simplified urban district model in laboratory
Summary
Flood events are one of the most dangerous natural phenomena connected to human activities, with possible consequences on people’s safety and economic losses [1]. For large scale modeling or when detailed geometry information are not available, flow obstructions may be represented as areas with higher roughness coefficient (roughness approach). This accounts for the increased resistance induced by the presence of buildings in the urban area. In most practical applications of flood simulation, the diffusive wave simplification is preferred to the full solution (dynamic wave), since the local and convective acceleration terms are small in comparison to the bed slope [16]. Geosciences 2018, 8, 77 simulation, the diffusive wave simplification is preferred to the full solution (dynamic wave), since the local and convective acceleration are of small in comparison to thebeen bed slope [16]. Simulation of a real flood event that hit the city of Olbia, Italy, on November 2013
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